Stuck on Loading page when coming in via Knox

Using Docker along with Zeppelin and latest knox 1.3.0. I can hit localhost:8080 to see zeppelin. When I use knox I get a "Loading" page with a spinning circle animation. I cant find anything in logs / etc. Tried multiple configs and blog referenced configs.

The knox config is reduced to simply:

```

<service>
<role>ZEPPELINWS</role>
<url>ws://localhost:8080/ws</url>
</service>
<service>
<role>ZEPPELINUI</role>
<url>http://localhost:8080/#/</url>
</service>

```

Any clues how to troubleshoot this or perhaps fix this? 

(I have removed ssl from the config to try and simplify the problem)